The heart-breaking story of former wrestling champion Ric Flair makes for a brilliantly compelling ESPN Films 30 for 30 documentary, "Nature Boy."

The stylin', profilin' Flair, whose real name is Richard Fliehr, was the ultimate showman during the pro wrestling boom of the 1980s. Even Hulk Hogan admits he couldn't hold a candle to Flair as a pure wrestler, ring tactician and entertainer. But as ESPN director Rory Karpf asks through his new documentary (Tuesday, 10 p.m. ET): "What if I told you his life wasn't an act?"

Outside the ring, The Nature Boy really did live the life of the "Rolex wearin’, diamond ring wearin’, kiss stealin’, wheelin’ dealin’, limousine ridin’, jet flyin’ son of a gun."

As he used to boast in his one-of-a-kind TV promos, Flair spent more money on spilled liquor at bars across America than most pro wrestlers made in a year. He boasted of the thousands of eager women who took a ride on "Space Mountain." He spent his fortune on fancy cars, jewels and clothes.

But the price the now 68-year-old Flair paid for becoming "The Man" was enormous. There was a string of broken marriages, resentful children, alcoholism, depression and IRS debts. Flair's personal life reached its nadir in 2013 when his 25-year-old son Reid Flair died of an accidental heroin overdose.

You'll hear Flair's heart-breaking call to 911 as he tries to save his dying son. The voice doesn't sound like The Nature Boy. He sounds like any panicked parent pleading for somebody, somewhere to save their child.

Flair admits to neglecting his two children from his first marriage, but Reid was special. We see in the documentary how Flair groomed him, introducing him to pro wrestling and allowing him to drink with him and his wrestling buddies. Wrestler turned WWE executive Triple H even warns Flair that Reid has a drug problem. But Flair ignores him. The son adopts his father's hard-drinking, hard-living ways, leading to an early death.

When Karpf asks Flair about his son's overdose, Flair completely breaks down. His one wish? That he'd been a "dad" to his troubled son instead of a buddy. Broken in body and mind, Flair tries to drink himself to death to drown out the pain. The downward spiral culminates with Flair fighting for his own life during a hospital stay in August.

But "Nature Boy" isn't all tragedy. There's a great anecdote about a young Flair trying to quit wrestling school until he's slapped senseless and ordered back to the gym by tough-as-nails trainer Verne Gagne. From then on, despite his drinking and partying, Flair's devotion to the gym was second to none. Hogan notes how Flair wrestled hundreds of matches that lasted an hour or more, a feat he never pulled off once.

We learned how a pudgy former college football player from the Midwest envisioned himself as a sleek "blond bad guy" after a plane crash that broke his back in three places — then made the dream happen. Watching Flair throw himself off top ropes onto tables, you wonder how he ever survived.

In the doc, Flair credits Buddy Rogers, the original Nature Boy, and mentor Dusty Rhodes for inspiring his look and style. We learn about the origins of the trademark "Woo!" scream, the in-ring strut, the cars, robes and fancy threads.

We hear about Flair's impact on African-American athletes and the hip-hop community. "He represented what we wanted to be," notes rapper Snoop Dogg.

One of my favorite scenes is watching the Indianapolis Colts and college football teams pumping themselves up for games by reciting Flair's most famous lines. It's great to watch Flair taking a father's proud joy in his daughter Charlotte's success as a pro wrestler.

All that said, I wanted to learn more about the origin of Flair's "Wheelin-Dealin'" routine and the famous "Flair Flop," in which he appears to fall on his face after getting knocked around. I also would have cut the silly animated bits that undercut the more dramatic sections about his failures as a husband, father and friend. It was sad watching clips of Flair, still wrestling in his 50s, getting his pants literally pulled down by younger opponents.

But those objections are minor. ESPN's first and only doc about a pro wrestler ranks right up there with the best in the 30 for 30 canon.

The lesson here is: You reap what you sow.

The fame and fortune that Flair sought became a "disease" that cost him his son's life — and nearly his own. Triple H calls his friend the "consummate liar." But the person Flair lied to most was himself. As Flair told Mike Greenberg on "Mike & Mike in the Morning" this week, young wrestlers should emulate his enthusiasm and love of sport, but they should avoid the drinking, partying and profligate spending. Most importantly, they shouldn't "disrespect" their families the way he did.

As Triple H notes in the film, Flair's "legacy will also be probably what not to do in the business. ... I use Ric as an example sometimes with young talent (saying), ‘You can have it all and end up in a really precarious spot.'"

Still, over a four-decade career, no wrestler touched more fans, or had more of an impact on pop culture, than The Nature Boy.

This enthralling but painful documentary is must-see TV. Diamonds are forever, and so is Ric Flair.